Television advertisements have traditionally used viewership statistics such as those provided by Nielsen ratings to select which advertisements to show during a given program. This method for reaching potential markets is far less precise than Internet advertisement, which uses available knowledge of the web surfer's preferences (i.e., search terms) and past viewing history to place advertisements in a targeted manner so that the most relevant advertisements are seen by the people most likely to be interested in the products and services being advertised.
With the advent of digital television (DTV) standards such as DVB-H, Media-FLO™, T-DMB, and ISDB-T 1/3 segment, a wide range of mobile handset users and non-mobile digital television viewers become potential targets of advertisement.